On March 28 2011, we were advised from Nuclear Safety Commission of Japan
to enhance sampling surveys regarding water accumulated in underground
floor of the turbine buildings of Fukushima Daiichi Nuclear Power Station.
In order to verify any leakages to underground and sea, and safety, we
have been implementing the sampling surveys of subsurface water and
seawater.

Regarding sampling surveys of sub-drains, per the instruction from Nuclear
and Industry Safety Agency (NISA) on April 14, we will continue the same
kind of sampling surveys three times a week, and inform the result on the
next day of the survey.
                                                    (Previously announced)

We collected samples from sub-drains (subsurface water obtained and
managed in the site) near the turbine buildings of Fukushima Daiichi
Nuclear Power Station collected on August 22, and conducted nuclide
analysis. As a result, radioactive materials were detected as shown in the
attachment. 
Today, we reported the results to NISA and the government of Fukushima
Prefecture. 

Appendix1: Nuclide Analysis Results of Sub-drains (PDF 10.7KB) 
Appendix2: Radioactivity Density of Sub-drain (PDF 23.4KB)